The present invention relates to a workpiece feeding apparatus for a sewing machine used for leather products or the like wherein a workpiece is fed by wheels.
It is a conventional practice in workpiece feeding apparatus for sewing machines to hold a workpiece between wheels disposed at upper and lower positions so as to face each other for the workpiece to be fed out by driving the lower wheel. However, none of those workpiece feeding apparatus has been provided with anything like a workpiece reverse feeding function, in other words, the function of allowing a lower wheel to be rotated in the reverse direction. This is because the one-way clutch which is used to intermittently rotate the lower wheel only has the function of rotating the lower wheel in the forward direction and because it is not adapted to function in the reverse direction.
In a case where the reverse feeding described above is not available, a workpiece has to be turned around when reverse stitching or the like is desired, the user thus being forced to perform troublesome work. To deal with this problem, it is known that a feed dog used in a conventional sewing machine is employed in order to provide both forward and reverse feeding to a workpiece.
However, such a feed dog is designed to perform four motions simultaneously, that is, to and fro motions, and up and down motions, and to feed a workpiece out by engaging the same when it is raised. Therefore, in the case of a leather product workpiece, it is most likely that the surface of the leather product is scratched when it is fed out by the feed dog, which involves the problem that the product value is likely to deteriorate to a great extent.
It is an object of the present invention to provide a workpiece feeding apparatus for feeding a workpiece in forward and reverse directions by means of wheels, thus eliminating any risk of scratching the surface of a workpiece, even if the workpiece is a leather product.